Figure 3a Intensity Scales for the Screen Modes
Figure 3b Intensity Scales Variation with APL
The Intensity Scale (sometimes called the Gray Scale) not only controls the Image Contrast within all displayed images but it also controls how the Red, Green and Blue primary colors mix to produce all of the on-screen colors. The steeper the Intensity Scale the greater the on-screen image contrast and the higher the saturation of all displayed color mixtures.
Intensity Scale Accuracy
Logarithmic Intensity Scale
Figure 3a below shows the Intensity Scales for the sRGB, DCI-P3, and Vivid Modes. The sRGB and DCI-P3 Intensity Scales are idential and relatively straight and smooth, with a Gamma that is slightly smaller than the Standrd 2.20. The Vivid Mode Intensity Scale is Intentionally Steep and Variable.
Gamma is 2.12 for the sRGB and DCI-P3 Natural Modes and 2.49 for the Vivid Mode.
For the sRGB and DCI-P3 Natural Modes there only a very small Shift in the Intensity Scales with APL, with the Gamma varying from 2.12 for Low APL to 2.16 for 50% APL. As a result, the Image Contrast appears unchanged with with changing APL, and we then expect the Absolute Color Accuracy to also have small variations with APL, which is examined in Figure 4.
For the Natural sRGB and DCI-P3 Modes the Gamma is 2.12 for Low APL and 2.16 for 50% APL.